USCG Exam PracticeDiesel engine principles (motor propulsion)
In a four-stroke diesel engine, the camshaft is geared to run at what speed relative to the crankshaft?
- A. The same speed as the crankshaft
- B. Twice the crankshaft speed
- ✓ Half the crankshaft speedCorrect
- D. One-quarter the crankshaft speed
Why C is correct
In a four-stroke cycle, each cylinder fires once every two crankshaft revolutions, so the camshaft — which opens each valve once per cycle — is geared to run at half crankshaft speed. DOE-HDBK-1018 Vol.1 §1-1 states this explicitly.
Cited:DOE-HDBK-1018 Vol.1 §1-1